Commentary / book review: Island Biogeography: Paradigm Lost?

Abstract

news and update ISSN 1948‐6596 commentary / book review Island Biogeography: Paradigm Lost? The Theory of Island Biogeography Revisited, ed. by Jonathan B. Losos and Robert E Ricklefs Princeton University Press, 2009, 476 pp. ISBN 978‐0‐691‐13652‐3 http://press.princeton.edu/ It is axiomatic that we can answer only those questions that we ask, and paradigm shifts in any field of study often consist of dramatic changes in perspective that facilitate the emergence of a large number of new questions. This simple defini‐ tion certainly describes the impact “The Theory of Island Biogeography” (MacArthur and Wilson, 1967) had on ecology and biogeography. In a mat‐ ter of a few years, a largely descriptive, non‐ quantitative, historically‐oriented approach was largely supplanted by one that was quantitative and hypothesis‐testing, and heavily influenced by a single, visually simple, conceptually intriguing ecological model ‐ the iconic equilibrium model. Its strong emphasis on the impact of varying rates of colonization and extinction on species richness, and the implied levels of turnover in community composition, led quickly to the development of quantitative ecological models that were applied not only to islands but to island‐like habitats and habitat fragments, contributing greatly to the early development of conservation biology. These perspectives and insights continue to ramify, lead‐ ing ever further into broader and broader aspects of ecology and evolution, with no end apparent. In hindsight, it seems that MacArthur and Wilson’s 1967 book, and the earlier but less influential 1963 paper, mark the boundary of an epic sea‐ change: there is biogeography before the equilib‐ rium model, and there is biogeography after the model. Or so it would seem, and so it is viewed by some of the authors who participated in the con‐ ference held in 2007 that celebrated the contribu‐ tions of MacArthur and Wilson’s book and the paradigm shift it brought about, which led to the edited volume that is the subject of this review. But this narrative is certainly too simple in several ways. Perhaps it is inevitable that when a power‐ ful new idea becomes widely accepted and forms the basis of a dominant conceptual paradigm, it becomes iconic ‐ a symbol of a world‐view, a way of placing all new information into a single frame‐ work. In the case of MacArthur and Wilson’s book, it was not the volume in its entirety that became iconic so much as one specific component, one very specific graph ‐ the crossed, curving lines of the equilibrium model of island biogeography. For many researchers, that one graph became the MacArthur and Wilson theory, and gradually most other parts of the book were forgotten. And in the effort to test, refine, and apply the implications of those two curving lines, sometimes blinders came into existence, causing application of the theory to be limited only to those questions that arose from equilibrium model and the assumptions on which it relies. These two viewpoints ‐ MacArthur and Wil‐ son’s theory as the well‐spring of broad and con‐ tinuing conceptual insights, and the equilibrium model as constraining blinders that have inhibited the development of new questions and entirely new insights ‐ are polar ends of a spectrum of atti‐ tudes that are implicit or explicit in all of the 16 chapters that make up the new volume that cele‐ brates 40 years of research in the MacArthur ‐ Wilson paradigm. It is the breadth of world‐views in the chapters that, for me, made the book a fas‐ cinating array of ways of viewing biogeography and its place in science, and the place of the 1967 book in biogeography. Perhaps more than any‐ thing else, this edited volume makes it clear that biogeography and MacArthur and Wilson’s view of biogeography are not the same thing. Some of the differences in perspective are immediately apparent in the way the new book is introduced. The brief foreword, by Robert May, describes the 1967 book as a seminal contribution to theoretical ecology, and specifically to commu‐ nity ecology, to the extent that he uses the words “island” and biogeography” only in reference to © 2011 the authors; journal compilation © 2011 The International Biogeography Society — frontiers of biogeography 2.4, 2011